SCIENTIFIC UPDATE
By Reed Mangels, PhD, RD, FADA
Omega-3's?
Fish oil supplements are commonly promoted as a way to reduce the risk of heart disease and possibly of cancer because of their omega-3 fatty acid content. A large study called into question the benefits of fish oil supplements. Close to 26,000 older adults were studied. They took either 840 milligrams per day of omega-3 fatty acids from fish oil (460 milligrams of EPA and 380 milligrams of DHA) or a placebo that did not supply omega-3s. They didn't know which type of capsule they were taking. Study subjects took the capsules and their health was monitored over an average of five years. There was no significant difference between the groups in their risk of having a stroke, heart attack, breast cancer, prostate cancer, or colorectal cancer, or of dying from heart disease. This study suggests that omega-3 supplements had little or no effect on risk of cardiovascular events or cancer. The researchers noted, however, that taking omega-3s was associated with some reduction in risk of strokes and heart attacks in those who ate little or no fish. This merits further study and suggests that older adults who don't eat fish might benefit from an omega-3 supplement. Of course, there's no need to take fish oil — microalgae supplements supply omega-3s in a vegan-friendly form.
Manson JE, Cook NR, Lee IM, et al. 2019. Marine n-3 fatty acids and prevention of cardiovascular disease and cancer. N Engl J Med. 380:23-32.
Daily or Weekly Vitamin B12?
Vitamin B12 recommendations from many vegan groups, including The Vegetarian Resource Group, are based on calculating how much vitamin B12 is likely to be absorbed from supplements containing different amounts of vitamin B12. For example, in 2015 we said, "About 5% of the vitamin B12 in a supplement containing 25 mcg of vitamin B12 is absorbed. A lesser amount, 1% or less of the vitamin B12 in a supplement containing more than 100 micrograms of vitamin B12, is absorbed."1 A recent study examines whether these theoretical absorption rates actually apply in vegans and non-vegan vegetarians.
In this study,2 36 vegetarian (including vegan) adults who were marginally deficient in vitamin B12 based on their blood vitamin B12 levels, were randomly divided into two groups. During the 12 week study period, one group took 50 micrograms of vitamin B12 daily and the other group took 2,000 micrograms of vitamin B12 once a week. Blood vitamin B12 was rechecked throughout the 12 weeks. Both groups' blood vitamin B12 levels improved as did other indicators of vitamin B12 status so that, at the end of the study, they were no longer considered to be deficient. These results support recommendations to take vitamin B12 supplements either daily if you are using a lower dose (25-100 micrograms) or weekly for a higher dose of 2000 micrograms. One advantage of using a lower dose daily could be that you're less likely to forget to take your supplement if it is part of your daily routine. On the other hand, taking a larger dose one day each week, perhaps first thing Monday morning, may be easier for some people to remember to do. In any case, it's important to have a regular source of vitamin B12, whether fortified food or supplement.
1 Mangels R. 2015. Nutrition Hotline. Vegetarian Journal. Issue 4. https://www.vrg.org/journal/vj2015issue4/2015_issue4_nutrition_hotline.php
2 Del Bo C, Riso P, Gardana C, et al. 2018. Effect of two different sublingual dosages of vitamin B12 on cobalamin nutritional status in vegans and vegetarians with a marginal deficiency: A randomized controlled trial. Clin Nutr. pii: S0261-5614(18)30071-2. [Epub ahead of print].
South Asian Americans Benefit from Vegetarian Diets
South Asians, those who come from India, Pakistan, and other parts of the Indian subcontinent, have higher rates of type 2 diabetes and heart disease than do non-Hispanic whites in the U.S. A study compared risk factors for these diseases between South Asians who follow vegetarian diets and those who don't. Close to 900 South Asian adults in the U.S. were studied. About 40% were categorized as vegetarian, meaning they reported not eating meat, poultry, or fish in the previous year. Vegetarians were more likely to eat whole grains and dried beans and less likely to eat sweets and eggs. Both groups used dairy products. On average, vegetarians had a lower BMI, lower waist circumference, lower total and LDL ("bad") cholesterol, lower fasting glucose, and lower risk of fatty liver. These results suggest that choosing a vegetarian diet may be helpful in reducing the risk of type 2 diabetes and heart disease in South Asians.
Jin Y, Kanaya AM, Kandula NR, et al. 2018. Vegetarian diets are associated with selected cardiometabolic risk factors among middle-older aged South Asians in the United States. J Nutr. 148:1954-1960.
Lead Found in Spices And Herbal Remedies
Keeping lead away from children is important because even low levels of lead can compromise mental development and growth. Lead exposure is assessed by
measuring blood lead levels. Recently, a group of children was found to have elevated blood lead levels. The children didn't live in houses with lead paint, and so investigators were puzzled about the lead source. They determined that the lead came from spices, herbal remedies, and ceremonial powders used in the children's homes. Ceremonial powders are used for social and religious markings and in Hindu religious worship. Items with especially high concentrations of lead included a saffron supplement, an Ayurvedic medicine, and turmeric. Non-food items that were high in lead included ceremonial powders and remedies applied to the skin. Other items had lower concentrations of lead; however, no amount of lead is considered safe for children. According to researchers, lead can contaminate spices because spices are often grown in countries with high soil and water lead levels. Lead can also come from the machinery used to grind spices. The FDA does not consider spices to be a food intended for consumption by children, and so the FDA does not recall contaminated spices. Clearly, regulations requiring increased testing of spices and herbal remedies for lead are needed. In the meantime, public health professionals recommend keeping ceremonial powders out of the reach of children. Testing blood lead levels regularly in children who frequently consume spices and herbal remedies could allow for earlier detection and treatment of elevated blood levels.
Angelon-Gaetz KA, Klaus C, Chaudhry EA, Bean DK. 2018. Lead in spices, herbal remedies, and ceremonial powders sampled from home investigations for children with elevated blood lead levels — North Carolina, 2011-2018. MMWR Morb Mortal Wkly Rep. 67:1290-1294.
People with Type 2 Diabetes Benefit from Vegan And "Plant-Based" Diets
"Plant-based" diets appear to offer significant benefits compared to other types of diets used to treat people with type 2 diabetes.1 Researchers identified 11 published articles in which a diet described as "plant-based" or "vegan" was used to treat type 2 diabetes. Eight studies used a vegan diet; others used a "plant-based" diet described as "avoid[ing] the consumption of most or all animal products and support[ing] high consumption of fruits, vegetables, legumes, seeds, whole grains and nuts." Overall, the vegan/"plant-based" diets were associated with improved quality of life, less depression, and less pain due to diabetic neuropathy (nerve damage). Additionally, those subjects on a vegan/"plant-based" diet tended to have better diabetes control, greater weight loss, and a greater reduction in total and LDL cholesterol. Compared to more traditional diets for diabetes, the vegan/"plant-based" diets were better accepted by study subjects. These results support guidelines from the American Association of Clinical Endocrinologists suggesting that primarily "plant-based meal plans" are the optimal nutrition plan for people with diabetes.2
1 Toumpanakis A, Turnbull T, Alba-Barba I. 2018. Effectiveness of plant-based diets in promoting well-being in the management of type 2 diabetes: a systematic review. BMJ. Open Diabetes Res Care. 6(1):e000534.
2 Garber AJ, Abrahamson MJ, Barzilay JI, et al. 2018. Consensus Statement by the American Association of Clinical Endocrinologists and American College of Endocrinology on the comprehensive type 2 diabetes management algorithm — 2018 executive summary. Endocr Pract. 24:91-120.
